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ABB MEASUREMENT & ANALYTICS | INSTRUCTION MANUAL | IM/2867 REV. Q
2867 series
pH and Redox (ORP)
industrial dip electrode systems
Measurement made easy
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Data Sheet
pH and Redox (ORP) industrial dip electrode systems
—
2867 series
pH/redox (ORP)
electrode systems
Electrical safety
This equipment complies with the requirements of CEI/IEC
for Measurement, Control and Laboratory Use’. If the
equipment is used in a manner NOT specified by the Company,
the protection provided by the equipment may be impaired.
Health and safety
To ensure that our products are safe and without risk to health,
the following points must be noted:
• The relevant sections of these instructions must be read
carefully before proceeding.
• Warning labels on containers and packages must be
observed.
• Installation, operation, maintenance and servicing must
only be carried out by suitably trained personnel and in
accordance with the information given.
• Normal safety precautions must be taken to avoid the
possibility of an accident occurring when operating in
conditions of high pressure and/or temperature.
• Chemicals must be stored away from heat, protected from
temperature extremes and powders kept dry. Normal safe
handling procedures must be used.
• When disposing of chemicals ensure that no two chemicals
are mixed.
Safety advice concerning the use of the equipment described in
this manual or any relevant hazard data sheets (where
applicable) may be obtained from the Company address on the
back cover, together with servicing and spares information.
1
CONTENTS
This manual describes the Industrial dip electrode system
Model 2867. Electrode assemblies for use with the system
incorporate electrodes of either glass or antimony for pH
measurements, or platinum for redox measurements.
1.1 Description
This system is constructed in plastic throughout and consists
of an ABS tube, with a transparent perspex section
incorporated in its upper half, supported by a mounting flange
or bracket. The electrode assembly is screwed into the lower
end of the system and sealed with an 'O'-ring.
The system tube is filled with salt-bridge solution forming an
integral reservoir for the reference element mounted in the
upper end of the electrode assembly. A liquid junction with the
sample solution is made at a ceramic plug fitted in the wall of
the system tube at its lower end. The connecting cable to the
electrode assembly passes through the system tube and out
through a rubber bung closing the upper end of the system.
The system is made in three standard lengths permitting
immersion of the electrodes in the solution to be measured to
nominal depths of up to 457 mm (18 in), 915 mm (36 in) or
1830 mm (6 ft). On both versions the mounting flange or
bracket is located by two rubber 'O'-rings.
The Model 2867 will operate in sample temperatures over the
range 0 to 70°C and is specially designed so that temperature
variation effects are reduced to a minimum.
1.2 Ancillary Equipment
Electrode Assemblies
Dual electrodes specially designed for use with the Model
2867 system are available as assemblies for direct mounting.
The assembly consists of a combined measuring/reference
electrode contained in an ABS plastic tube. The membrane of
the measuring electrode projects through the lower end of the
tube: the reference element projects through the upper end of
the tube.
Assemblies available are as follows:
Model No. Type Application
1912 400 Glass pH
1980 430 Platinum Redox
1990 400 Antimony pH
1912 500 Glass pH
1980 530 Platinum Redox
1990 500 Antimony pH
Note. See List of Spares for ordering information.
1 INTRODUCTION
Contents Page
1 INTRODUCTION............................................................. 1
1.1 Description ............................................................. 1
1.2 Ancillary Equipment ............................................... 1
2 INSTALLATION .............................................................. 2
2.1 Mounting ................................................................. 2
2.2 Electrical Connections............................................ 2
3 PREPARATION FOR USE ............................................. 2
3.1 Activation of Electrodes ......................................... 2
3.2 Assembly of the System......................................... 2
3.3 Standardisation pH ................................................. 2
3.4 Standardisation Redox ........................................... 3
4 ROUTINE MAINTENANCE ............................................ 3
4.1 Salt Bridge Solution................................................ 3
4.2 Standardisation ...................................................... 3
4.3 Cleaning ................................................................. 3
4.3.1 Glass Electrodes ........................................ 3
4.3.2 Platinum Electrodes: .................................. 4
4.3.3 Antimony Electrodes .................................. 4
4.3.4 Ceramic Plug: ............................................. 4
4.4 Care of Plugs and Sockets .................................... 4
5 SERVICING ................................................................... 4
5.1 Removal of Electrode Assembly ............................ 4
5.1.2 Replacement of Electrode assembly ......... 4
5.2 Fault Finding........................................................... 4
6 LIST OF SPARES ........................................................... 5
fitted with BNC
coaxial connectors
fitted with tagged ends
NOTE. Electrode assemblies:
1980 400
1980 500
have now been replaced with the following assemblies
respectively:
1980 430
1980 530.
The former assemblies are now discontinued for
environmental reasons, in line with Company policy.
2
2.1 Mounting
a) Dimensions of the flange and fixing holes are shown in Fig.
1 together with overall dimensions of the complete system.
b) Since the associated measuring instrument has to be set
up with the electrode immersed in standardising solutions,
the electrode system should not be bolted into place until
the standardisation procedure (see under OPERATION)
has been carried out. Correct alignment of the fixing holes
for the installation should however be checked before
standardisation.
c) It is important to ensure that the system is so positioned as
to ensure a positive head of 300 to 600mm (12 to 24in) of
salt bridge solution relative to the liquid being measured.
2.2 Electrical Connections
The connecting cable is fitted with a waterproof coaxial plug or
tagged ends.
a) Remove the protecting end cap (supplied with the versions
fitted with coaxial connectors) and retain it for future use. It
will be required if the electrode assembly is removed or
otherwise disconnected from the measuring instrument.
b) Ensure that any dirt or grease in the plug and associated
socket connected to the measuring instrument is removed
by carefully wiping with a rag moistened with a suitable
solvent e.g. propanol.
c) Connect the plug and socket and make watertight by
overlapping the rubber sleeves provided.
d) For electrodes with cables terminating in tagged ends,
connect the individual tags to the input terminal block of the
pH meter, as described in the instruction manual for the pH
meter.
3.1 Activation of Electrodes
Before use, depending on the type of electrode assembly a
period of activation may be required. Full details are given in
the booklet provided with the electrode assembly.
3.2 Assembly of the System
a) Remove the split rubber bung from the cap on the upper
end of the system.
b) Fit the smaller of the ceramic plugs to the side of the
electrode system tube (See Fig. 1) using the special
wrench supplied in the accessory kit. If the sample causes
blockage of the ceramic, replace the plug with the larger
one, which will allow a higher flow of salt bridge solution.
c) Thread the coaxial cable from the electrode assembly up
through the bottom end of the system so that it passes out
through the cap on the upper end.
d) Remove the neoprene cap from the salt bridge solution
entry tube of the reference element (at the upper end of the
electrode assembly).
Note. There should be a minimum of delay between
carrying out this step and the filling of the system with salt
bridge solution (see below).
e) Screw the electrode assembly into the system and tighten
firmly until it is flush.
f) Unscrew the cap on the upper end of the system. There is
no need to remove it from the coaxial cable.
g) Holding the system upright, fill with salt bridge solution
(saturated potassium chloride) until the level can be seen
to be near to the top of the transparent section. Add a few
grammes of KCl crystals to keep the solution saturated.
h) Place the screw cap on the upper end of the system.
i) Fit the coaxial cable into the split rubber bung and place it
in the cap.
3.3 Standardisation pH
This consists of setting up the associated measuring
instrument to read correctly with the electrode in the system
immersed in suitable standard solutions. The procedure is fully
described in the appropriate instrument manual.
Note. When using a glass electrode assembly the check
reading to be expected is between 6.7pH and 7.3pH.
When the standardisation procedure has been carried out,
complete the installation of the system.
2 INSTALLATION 3 PREPARATION FOR USE
3
3.4 Standardisation Redox
A method of checking redox electrode pairs
The normal method of checking a redox pair is to immerse the
electrodes in solutions of known redox potential. The
standards used are quinhydrone/pH solutions prepared by
making up standard ABB Kent-Taylor 4 and 7pH buffer
solutions and saturating both by adding excess quinhydrone.
A redox electrode pair is then immersed in the solutions in turn
and the readings noted. The values of the e.m.f. as measured
at 25°C are shown below. Readings should be within ±15mV.
This consists of keeping the system topped up with salt
bridge solution, checking the standardisation of the
electrodes against buffer solutions, and making periodic
checks to ensure that the electrode membrane and ceramic
plug are clean.
4.1 Salt Bridge Solution
The saturated KCl salt bridge solution should be topped up
weekly. The level must not be allowed to fall below the
transparent perspex section, otherwise it could fall undetected
below the entry tube of the reference element.
4.2 Standardisation
Standardisation should be carried out at regular intervals. The
precise interval will depend on the use of the electrode and
cannot be stated definitely, but normally should take place
weekly, or more frequently if conditions demand it. At first,
carry out daily checks, and then extend the interval in the light
of experience.
4.3 Cleaning
a) The need for cleaning the electrode becomes apparent
when the response becomes sluggish, with possibly a
falling off in calibration.
b) If the cleaning procedures described below do not
eliminate these symptoms, the electrode assembly and/or
ceramic plug should be changed.
c) During cleaning, avoid rough handling of the electrode
membrane. Wiping with a cloth soaked in suitable solvent
for the deposit, or washing with a strong jet of water, are
preferred methods.
d) Where the cleaning process for the electrode or ceramic
plug necessitates soaking for a time, it is advisable to
exchange the electrode system with a standby system, so
that there is least interruption to the measurements.
Warning. DO NOT USE ORGANIC SOLVENTS THAT
MAY ATTACK THE ABS PLASTIC MATERIAL USED IN
THE CONSTRUCTION OF THE SYSTEM AND
ELECTRODE ASSEMBLY.
4.3.1 Glass Electrodes
Methods of removing various types of deposit are given below:
General sludge and loosely adhering matter:
Direct a strong jet of water onto the glass membrane.
Light Inorganic Deposits:
Wipe the glass with cotton wool soaked in 0.1M HCl and then
wash in water before standardising.
Greasy Organic Deposits:
Wipe the glass with cotton wool soaked in a non-ionic
detergent and rinse thoroughly. If sluggishness is still
observed, soak the electrode for a few hours in 0.1M HCl and
then wash in water before standardising.
…3 PREPARATION FOR USE 4 ROUTINE MAINTENANCE
noituloSlCgA/gAvtP
Hp4Vm952+
Hp7Vm28+
Table 3.1 E.m.f. values for Pt vs Ag/AgCl Reference
Electrode
4
Heavy Non-Greasy Deposits: (e.g. rust, chalk)
Wipe` with cotton wool soaked in concentrated HCl to remove
the deposit, and rinse thoroughly. Soak the electrode for a few
hours in 0.1M HCl and then wash in water. An alternative
treatment is to wipe the electrode and soak it overnight (or
longer if necessary) in a 10% solution of E.D.T.A. followed by
reactivation in 0.1M HCl and rinsing in water.
Heavy deposits formed during effluent neutralisation are often
removed by using a 1:1 mixture of concentrated HCl and
water.
4.3.2 Platinum Electrodes:
In general, the same procedures may be used as for glass
electrodes. They may also be cleaned cathodically.
4.3.3 Antimony Electrodes
Emery paper or a file should be used
4.3.4 Ceramic Plug:
The same procedures may be used as for glass electrodes,
but lengthy soaking should not be necessary. In general, the
ceramic plug need not be removed. A heavily fouled ceramic
plug may still perform satisfactorily, but if found to be the
source of reduced system performance the plug and seal
should be replaced together. The seal is removed by careful
easing out with a spanner or the special wrench provided.
4.4 Care of Plugs and Sockets
Plugs and Sockets should be examined every time they are
disconnected. Dirt or grease should be removed by wiping with
a clean cloth moistened with a solvent e.g. propanol. The
centre contact of sockets should also be examined to make
sure that the two halves have not spread too far apart to grip
the plug contact firmly. Gentle pressure with pliers should be
used to bring the contacts together again.
5.1 Removal of Electrode Assembly
The procedure is as follows:
a) Disconnect the waterproof plug on the coaxial cable
connected to the electrode system from the coaxial socket
connected to the measuring instrument.
b) Fit the waterproof cap to the coaxial plug (when supplied)
c) Remove the system tube from the sampling point, ensuring
that the process solution is not under pressure. KEEP
TUBE UPRIGHT.
d) Rinse off the solution so that the electrode assembly may
be handled.
e) Remove the split rubber bung holding the coaxial cable in
place in the upper end of the system.
f) Unscrew the cap in the upper end of the system and empty
the salt bridge solution into a clean vessel (the solution
may be kept and used for refilling).
g) Hold the end of the electrode assembly in one hand and
the lower part of the system tube in the other. Unscrew the
electrode assembly anticlockwise until it is free of the
system.
h) Remove the screw cap from the coaxial cable by passing it
over the plug end.
i) Gently draw the coaxial cable and plug through the system
tube so that the electrode assembly and cable are free.
j) Hold the system tube upside down and wipe the inside,
where the electrode assembly fits, with absorbent paper.
This prevents a layer of KCl crystals forming as any salt
bridge solution left dries out.
5.1.2 Replacement of Electrode assembly
Carry out the procedure described under 3 PREPARATION
FOR USE, removing the cap from the reference element if the
assembly is a new one.
5.2 Fault Finding
The location of a fault is best found by fitting a replacement
electrode assembly and carrying out a standardisation check.
If changing the electrode assembly clears the fault, then the
assembly is faulty and should be checked to see if it can be
restored to working order. If, after cleaning and reactivating the
electrode assembly, cleaning or changing the ceramic plug
and refilling with fresh salt bridge solution, there is no
improvement, then the old electrode assembly should be
discarded.
If the fault is in neither the electrode assembly nor the ceramic
plug, it must be assumed that the measuring instrument or its
connections are faulty.
The following is a short (and by no means exhaustive) list of
fault symptoms and the possible causes due to faulty
electrodes.
…4 ROUTINE MAINTENANCE 5 SERVICING
5
…5 SERVICING
Table 5.1 Fault Finding
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.tekcosdnagulpfoorpretawehtkcehC.tiucricneposdaeledortcelE)a
.edortceleecnereferehtfolevelehtwolebnellafsahnoitulosegdirbtlaS)b
.pupoT
kcehctaselttesrehtiegnidaerrotacidnI.2
.gnidaerrehtoemosro,gnidaer
.tekcosdnagulpfoorpretawehtkcehC.tiucrictrohssdaeledortcelE)a
.ylbmessaedortcelewentiF.dekcarcenarbmemedortcelE)b
.stfirdgnidaerrotacidnI.3
.gulpehtegnahcronaelC.ytridrodekcolbgulpcimareC)a
.ylbmessaedortcelewenayrT.dehtraedaeledortceleecnerefeR)b
tlasfodaehtneiciffusnioteudebdluoC.denosiopedortceleecnerefeR)c
cimarecehthguorhtssapotsecnatsbussuoirujnigniwolla,noitulosegdirb
.noitulosegdirbtlasfodaehretaerghtiwylbmessaedortcelewenyrT.gulp
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.levelretemarapnisegnahcotesnopser
.etavitcaerdnanaelC.detaocroytridenarbmemedortcelE)a
.hsiggulssiesnopseredortceleserutarepmetwolyrevtA)b
6
6 LIST OF SPARES
rebmuNtraP
rotcennoClaixaoCrotcennoCCNBsgaT
gulpCNB151832000421910052191
tekcosCNB944832003408910350891
)gulpmm5.3(ylbmessagulpcimarecni-wercS055768200409910050991
)gulpmm5.1(ylbmessagulpcimarecni-wercS0457682
ylbmessagulpcimarecrofhcnerW0657682
)gnitnuomecafrus(egnalfgnitnuoM0467682
)gnitnuomllaw(tekcarbgnitnuoM0757682
reppotsrebburtilpS0247682
When ordering spares always quote the Part No. Spares should be ordered from ABB Limited, Oldends Lane, Stonehouse
Gloucestershire, GL10 3TA, England.
rebmuNtraP
cimarecdnasgnir-Ogniniatnoc–kcapecivreS
sgulp
1407682
slatsyrcedirolhcmuissatoP0710040
Hp4reffuB0110040
Hp7reffuB0210040
Hp32.9reffuB0310040
)32.9dna7,4(sreffubfoxobdexiM5310040
7
Fig. 1 Model 2867 Installation Diagram
27mm
(1
1
/16 in)
O-Ring Seal (0211 283)
Fits inside here
4 holes 14.3mm (
9
/16 in)
diameter on 82.5mm (3
1
/4 in)
PCD as shown
Optional flange for surface
fixing (Part No. 2867 640)
O-Ring seal
(0211 188)
fits here
Hole tapped 1/8in BSP for
ceramic plug assembly
Optional bracket for
wall mounting
(Part No. 2867 570)
114.3mm
(4
1
/2 in dia)
89mm
(3
1
/2 in)
2 holes 6.3mm (
1
/4 in)
diameter
855mm
(33
5
/8 in)
or
450mm
(17
3
/4 in)
270mm
(10
5
/8 in)
25.4mm (1in)
64mm (2
1
/2 in)
73mm
(2
7
/8 in)
127mm
(5in)
1160mm (45
5
/8 in)
or
755mm (29
3
/4 in)
715mm
(28
1
/8 in)
or
322mm
(12
11
/16 in)
140mm
(5
1
/2 in)
8
NOTES
Sales Service
IM/2867 Rev. Q 11.2018
—
We reserve the right to make technical changes or modify the contents of this document
without prior notice. With regard to purchase orders, the agreed particulars shall prevail.
ABB does not accept any responsibility whatsoever for potential errors or possible lack of
information in this document.
We reserve all rights in this document and in the subject matter and illustrations contained
therein. Any reproduction, disclosure to third parties or utilization of its contents – in
whole or in parts – is forbidden without prior written consent of ABB.
© ABB 2018
—
ABB Limited
Measurement & Analytics
Oldends Lane
Stonehouse
Gloucestershire
GL10 3TA
UK
Tel: +44 (0)1453 826 661
Fax: +44 (0)1453 829 671
Email: instrumentat[email protected]
ABB Inc.
Measurement & Analytics
125 E County Line Road
Warminster
PA 18974
USA
Tel: +1 215 674 6000
Fax: +1 215 674 7183
abb.com/analytical
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